A Johnstone wrote:
| We're looking at top down vs bottom up parsers with infinite
| lookahead. [...] are there any _languages_ which are
| inherently LR and not LL(oo)? (LL with infinite lookahead [...])

Jerry Leichter <leichter@smarts.com> writes:>I'm not sure what L(oo) would be.

Judging by the crossposting, I suspect A Johnstone was talking about LL
parsers with backtracking, as is supported by PCCTS. An LL(1) parser with
backtracking would not have any difficulty with your example language

> L = { x^{2n}y^{2n} e, x^{2n+1}y^{2n+1} o}

because it could try the first (even) alternative, and then if that
failed it could backtrack and try the other (odd) one.